1. Field of the Disclosure
This disclosure relates to an inorganic particle, in particular an inorganic oxide pigment particle, and more particularly a titanium dioxide pigment, TiO2, suitable for use in coatings, plastic and laminates.
2. Background of the Disclosure
Titanium dioxide pigments are prepared using either the chloride process or the sulfate process. In the preparation of titanium dioxide pigments by the vapor phase chloride process, titanium tetrachloride, TiCl4, is reacted with an oxygen containing gas at temperatures ranging from about 900° C. to about 1600° C., the resulting hot gaseous suspension of TiO2 particles and free chlorine is discharged from the reactor and must be quickly cooled below about 600° C., for example, by passing it through a conduit, i.e., a flue, where growth of the titanium dioxide pigment particles and agglomeration of said particles takes place.
It is known to add various substances, such as silicon compounds and aluminum compounds, to the reactants in order to improve the pigmentary properties of the final product. Silicon compounds added as a coating to the TiO2 particles are known to reduce photoactivity of the TiO2 particles and improve durability of paints produced from such pigments. Alumina compounds are known to improve the dispersability of the pigments produced.
A need exists for a process for the addition of silica, aluminum and zinc to inorganic oxide pigments, and in particular titanium dioxide pigments, that provides property improvements needed for making improved coatings, plastic and laminates.